A solar cell is a device that converts light into electrical energy. Measurements of opto-electrical properties are of a paramount technological importance. One example of opto-electrical properties is quantum efficiency of solar cells. A solar cell can be described as an active layer (the layer where conversion of light into electricity happens) sandwiched between two current collectors (electrodes). Quantum efficiency (QE) is a measure of solar cell performance, which is the percentage of photons hitting the photoactive surface that produce collected charge carriers. From a basic science point of view, QE mapping provides information about band structure of the absorber inside the solar cell, as well as a direct measure of performance improvements due to nanostructuring and light management strategies. From an applied point of view, QE mapping is a useful tool for quality control and failure analysis. It is usually measured by shining monochromatic light onto a photovoltaic cell and recording electrical output of the device. QE mapping is also useful for understanding performance degradation of solar cells, a ubiquitous problem in the solar cell industry. There are several mechanisms for performance degradation with degradation of the active layer and contacts being the most prevalent.
There is an unmet need for a system for efficient quality control and failure analysis for solar cells and other optoelectronic devices.